Method for producing data carriers with embedded elements

ABSTRACT

The card body of a data carrier with elements disposed therein, for example an electronic module, is produced from a pressed molding compound in a pressing apparatus. The elements to be embedded in the card body are preferably incorporated in the pressing apparatus and positioned and fixed there before the pressing operation.

FIELD OF THE INVENTION

This invention relates to a method for producing a data carrier with acard body having two plane-parallel main surfaces and at least oneelement, for example an electronic module or magnetic stripe, etc.,disposed therein. The invention furthermore relates to an apparatus forcarrying out this method.

BACKGROUND OF THE INVENTION

In the past various methods for producing data carriers of theabovementioned type have become known. For example multilayer datacarriers are produced by connecting individual layers under the actionof heat and pressure, which is generally referred to as the laminatingtechnique. Elements to be incorporated in the card body can thereby beinserted in the layer structure in specially provided recesses beforelamination. It has also been proposed to stamp single-layer card bodiesout of a foil, whereby a recess can be simultaneously produced, e.g. forreceiving an electronic module.

Finally it has become known e.g. from EP 0 277 854 B1 to manufacturedata carriers with an embedded electronic module by injection molding.One provides an injection mold having a cavity whose dimensionscorrespond to those of the data carrier. Before injection of the plasticcompound the electronic module is placed in the cavity on one half insuch a way that the contact surfaces of the module lie flat against thehalf of the cavity and are fixed in this position by suction air. Afterthat the plastic compound is injected via a lateral edge of the mold toform the card body so that the module is surrounded in form-fittingfashion by plastic compound. Suitable shaping of the casting compound ofthe electronic module causes the latter to be anchored reliably in thecard body. The data carrier can now be removed from the mold.

To guarantee reliable fixation of the electronic module in the cavityduring the injection process one can take additional measures. Forexample the module can be urged by a spring-mounted plate against thecavity half to which it is fixed which is lowered during injection ofthe plastic compound.

One obtains uniform and complete filling of the cavity with plasticmaterial in injection molding by injecting the material into the cavityat very high pressure. This involves relatively elaborate apparatussince one must produce the high injection pressure, on the one hand, andapply high locking forces to the cavity to prevent its halves from"spreading apart" during the injection process, on the other hand. Thismakes injection molding tools quite expensive, so that injection moldedarticles in general and injection molded data carriers in particular canfrequently be manufactured rationally only in high numbers.

SUMMARY OF THE INVENTION

It is therefore the object of the invention to propose a new method andan apparatus for producing single- or multilayer data carriers in whichone of the abovementioned elements is optionally embedded.

This problem is solved by the characterizing features of the independentclaims.

The basic idea of the invention is that at least part of the datacarrier is produced by the pressing method by pressing plastic granularmaterial or powder. The elements to be optionally embedded in the cardbody are preferably incorporated at the desired position in the plasticgranular material or powder located in the pressing apparatus, and theplastic granular material or powder only then pressed.

The new method thus has the decisive advantage that the elements to beembedded in the card body are already surrounded completely by plasticcompound before the actual pressing operation. The actual materialforming process by the pressing operation is thus independent in termsof time from the embedding of the elements in the plastic compound andone can completely or largely dispense with additional aids forpositioning and fixing the elements. Simultaneously the elements areincorporated in the card body especially gently since they are alreadyprotected by the surrounding plastic compound during the pressingoperation.

The advantages obtained with the invention are also to be seen in thefact that the apparatus for carrying out the method need not beelaborate. A pressing apparatus thus comprises only a die which ischarged with plastic granular material and softened there, and apressure ram for giving the softened plastic compound the desired shape.One can also mix additives locally with the plastic granular material insimple fashion for producing certain effects in the finished card bodyof the data carrier. Finally, a homogeneous distribution of the plasticmaterial arises during the pressing operation without preferreddirections in the molecular orientation which can lead to breakingpoints in the data carrier.

According to a first embodiment example of the invention one produces adata carrier containing in its interior an additional element, forexample an electronic module for noncontacting data exchange. For thispurpose the die is charged with a first quantity of plastic granularmaterial and the element placed on the resulting first layer and coveredwith a second quantity of plastic granular material, so that the elementis located between two layers and surrounded completely by plasticmaterial. The granular material is then softened and pressed with thepressure ram to form the card body.

According to a further embodiment example of the invention one producesa data carrier containing an additional element located partly on thesurface of the card body, for example an electronic module forcontacting data exchange. For this purpose the die is charged with ameasured quantity of plastic granular material, and the element eitherembedded in the plastic granular material at the desired position orpressed into the softened granular material with the help of thepressure ram.

According to a third embodiment example of the invention the die orpressure ram has raised areas for forming recesses, when the softenedplastic material is pressed, for receiving elements in the card body. Inthis case the elements are incorporated in the card body in a separatemethod step.

Finally, according to a further embodiment example of the invention thedata carrier can be provided during the pressing operation with coverfoils which are inserted in the mold cavity and on which additionalelements are optionally mounted. For example a foil with magneticstripes can be inserted in the die and the die then charged with plasticgranular material which connects with the foil during the pressingoperation, as in the laminating technique.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiment examples and further advantages of the invention will beexplained more closely in connection with the following figures, inwhich

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a data carrier in plan view,

FIG. 2a shows a pressing apparatus in cross section,

FIG. 2b shows an element inserted in the pressing apparatus in planview,

FIG. 3 shows a pressing apparatus in cross section,

FIG. 4 shows a pressing apparatus with raised areas in cross section,

FIG. 5a shows a carrier foil in plan view,

FIG. 5b shows a pressing apparatus with inserted foils in cross section.

FIG. 1 shows a data carrier in plan view. The data carrier hasdimensions defined in an ISO standard designated ISO 7810. In the mainsurfaces of data carrier 1 different elements can be embedded dependingon its use, for example electronic module 3, magnetic stripe 5 orhologram 7. For certain applications of the data carrier the elementscan also be located in the interior of the card body, e.g. an electronicmodule for noncontacting data exchange. Those elements located partly onthe surface of the card body are in a predetermined or standardizedposition.

FIG. 2a shows in cross section a pressing apparatus consisting of die 9and pressure ram 11 with end face 12 which corresponds to the mainsurface of the card body. Die 9 contains recess 13 whose base surfacecorresponds to the main surface and whose depth at least to thethickness of the card body. With the pressing apparatus open, recess 13in die 9 is charged with a measured quantity of molding compound 15,consisting e.g. of plastic granular material or plastic powder, which isnecessary for producing the desired molding, in this case card body,with a predetermined thickness. Molding compound 15 is then heated tothe point of flowability so that it fills under pressure the entire moldcavity arising between pressure ram 11 and die 9 when the pressingapparatus is closed. When the card body has hardened the pressingapparatus is opened and the card body removed or ejected. Die 9 andpressure ram 11 are generally fastened to the upper and lower mountingplates of a press and continuously heated or designed to be heatable andcoolable.

As FIG. 2a shows, an element, e.g. an electronic module fornoncontacting data exchange, is embedded in molding compound 15 so thatit is surrounded on all sides by molding compound and thus located inthe interior of the completed card body. For this purpose recess 13 isinitially charged with a first quantity of molding compound 15 on whichelectronic module 3 is placed. Recess 13 is then charged with a secondquantity of molding compound 15. This basically completes the shaping ofthe card body; molding compound 15 need only be heated and pressed. Bothduring shaping of the card body and during the following steps embeddedelectronic module 3 is held in position exclusively by molding compound15 so that no additional holding devices are necessary, as in injectionmolding for example. One nevertheless obtains a card body whose embeddedelement is surrounded by molding compound in form-fitting fashion.

It is also possible to provide molding compound 15 with certainadditives, e.g. for producing certain properties in the card body. Forexample, if an electronic module for inductive data exchange is embeddedin the card body one can add ferrite powder to the molding compound toimprove the quality of the module coil and thus the energy input to themodule.

It is furthermore possible to provide molding compound 15 with differentadditives in different layers. The molding compound located on thesurface of the completed card body of the data carrier can be providedfor example with additives which allow lasering of the surface, and theintermediate molding compound can be provided with ferrite powder asexplained above. To obtain such a distribution, the recess of the die ischarged with molding compound several times in accordance with thedesired layers in the completed card body. Pressing of the moldingcompound thus gives rise to a basically single-layer card body which isnevertheless provided with different additives in different areas.

For producing semifinished products the recess in the die can also becharged with a quantity of molding compound smaller than the quantitywhich would be necessary for producing a molding in card thickness. Themolding instead has a smaller thickness and can be provided withseparately produced cover layers after removal from the pressingapparatus for completing the data carrier. For producing a semifinishedproduct it is thus unnecessary to provide a special tool, as requirede.g. in injection molding.

FIG. 2b shows in plan view electronic module 3 for non-contacting dataexchange embedded in the data carrier. It consists of e.g. wire-wrappedcoil 17 whose ends are electrically connected with contact surfaces 21located on carrier film 19. Integrated circuit 23 is applied to the sideof carrier film 19 opposite contact surfaces 21, being connectedelectrically with contact surfaces 21 e.g. by bonding wires 25 leadingonto said surfaces through corresponding windows in carrier film 19. Tobe protected from mechanical loads bonding wires 25 and integratedcircuit 23 can be sealed with a casting compound.

FIG. 3 shows in cross section a pressing apparatus consisting of die 9and pressure ram 11. Pressure ram 11 contains suction apparatus 27 forpositioning and fixing electronic module 3 on pressure ram 11 by suctionair applied from outside in such a way that contact surfaces 21 ofmodule 3 lie flat against the pressure ram. When pressure ram 11 islowered into recess 13 of die 9 the electronic module is pressed at thespecially provided position into molding compound 15 heated to the pointof flowability. Fixation of the element on the end face of the pressureram is thereby supported by the acting pressure, so that the elementneed only be fixed lightly to the ram. One thus obtains a data carriercontaining an electronic module in the predetermined or standardizedposition. Other elements which are partly located on the surface of thedata carrier can of course also be pressed into the card body in thestated manner. It is likewise possible to position and fix the elementsin the recess instead of on the end face of the ram.

As an alternative to fixing the element on the end face of pressure ram11 it is also possible to position the element directly in moldingcompound 15 after die 9 is charged therewith. Fixation of the element inposition is then given exclusively by the surrounding molding compound.This procedure is especially favorable when it is unnecessary toposition the elements in the completed data carrier very exactly, e.g.according to a standard.

FIG. 4 shows in cross section a pressing apparatus whose die 9 andpressure ram 11 have raised areas 29, 31 for forming recesses in thecard body of the data carrier during the pressing operation in whichcorresponding elements are incorporated later. For example raised area31 in the end face of pressure ram 11 gives rise to a recess forreceiving an electronic module in the card body. Such a design of thepressing apparatus is particularly favorable when the card body isproduced and the elements embedded therein at different places.

FIG. 5a shows in plan view cover layer 33 with the size of the mainsurface of a data carrier. The cover layer can be used as a carrier foilfor one of the elements to be embedded in the data carrier. For examplea magnetic or signature stripe or a hologram can be embedded in thecover layer. If cover layer 33 is to be used as a carrier foil for anelectronic module it contains contact surfaces 21 below which windowsare located (not shown). Furthermore cover layer 33 can contain ahigh-quality printed image and alphanumeric data 35 e.g. relating to thelater card owner.

FIG. 5b shows in cross section a pressing apparatus consisting of die 9and pressure ram 11. Cover layer 37 is first inserted in recess 13 ofdie 9 in such a way that the bottom of recess 13 is covered completelyby the cover layer. Additional suction apparatus can be provided in thebottom area of recess 13 for fixing cover layer 37. After cover layer 37is inserted recess 13 is charged with a measured quantity of moldingcompound 15 on which cover layer 35 is then placed. On the side of coverlayer 35 opposite the contact surfaces integrated circuit 23 is glued inthe area of contact surfaces 21 and electrically connected with contactsurfaces 21 by bonding wires led onto said surfaces through windows 39.To be protected from mechanical loads bonding wires 25 and integratedcircuit 23 are sealed with a casting compound.

During the pressing operation molding compound 15 softened to the pointof flowability connects with cover layers 33 and 37, giving rise to amultilayer data carrier. Cover layers 33 and 35 can consist for exampleof a plastic material which connects especially well with the moldingcompound and be additionally coated inside with a thermally activatedadhesive to improve the bond between the layers. The above-mentionedmethod thus produces a multilayer data carrier with embedded elements insimple fashion, whereby the cover layers of the data carrier can beprovided with very high-quality printed images.

Although the figures show pressing apparatus for single card production,it is naturally also possible to provide pressing apparatus in whichseveral cards can be manufactured simultaneously. In this case the dieneed only have a plurality of recesses in card size and the pressure rama corresponding multiple design. Alternatively it is also possible tofirst manufacture a large plastic plate in the pressing apparatus out ofwhich the data carriers are later punched or cut.

Finally it should be mentioned that the shown embodiment examples raiseno claim to completeness. It is e.g. possible to combine differentembodiment examples with one other without departing from the inventiveidea. For example one can provide the card body whose production isshown in FIG. 2a with cover layers on both sides by proceeding in theway explained in connection with FIG. 5b.

We claim:
 1. A method for producing a data carrier having a card bodycomprising two plane-parallel main surfaces and at least onedata-carrying element, said method comprising the following steps:(a)providing a pressing apparatus having a pressure ram whose end facecorresponds to one of said main surfaces of the card body and a die witha recess whose base surface corresponds to one of said main surfaces andwhose depth corresponds at least to the thickness of the card body, (b)charging the recess of the die with a measured quantity of moldingcompound comprising one of a plastic granular material and a powder, (c)heating the molding compound in said recess to the point of flowability,(d) performing a pressing operation by lowering the pressure ram intothe recess of the die and pressing the molding compound in said recesswith the pressure ram until the molding compound in the recess assumesdesired dimensions to form said card body, (e) returning the pressureram and removing the card body from the pressing apparatus, and (f)performing an operation comprising causing said element to be one of (i)at least partially embedded in said card body and (ii) disposed at leastpartly on one of said main surfaces of said card body.
 2. The method forproducing a data carrier of claim 1, wherein:step (b) comprises chargingthe recess of the die with a first measured quantity of said moldingcompound so that the recess is filled with a first layer of said moldingcompound, step (f) comprises placing said element on the first layer insaid recess, and step (b) further comprises charging the recess of thedie with a second measured quantity of said molding compound to form asecond layer of said molding compound so that said element is locatedbetween said first and second layers of the molding compound andsurrounded thereby on all sides.
 3. The method for producing a datacarrier of claim 1, wherein step (f) comprises pressing said elementinto the molding compound during pressing of the molding compound withthe pressure ram such that when said data carrier is completed, saidelement is located at least partly on one of said main surfaces of saidcard body.
 4. The method for producing a data carrier of claim 3,wherein step (f) comprises positioning a part of the element such thatsaid part is directly located on an end face of the pressure ram andfixed in position there until said pressing operation is completed. 5.The method for producing a data carrier of claim 3, wherein step (f)comprises inserting the element, before initiation of said pressingoperation, into the molding compound located in the recess so as to beheld in position by said compound.
 6. The method for producing a datacarrier of claim 1, wherein the pressure ram has raised areas forforming, when the molding compound is pressed, recesses in the card bodyinto which said element can later be embedded.
 7. The method forproducing a data carrier of claim 1, wherein step (b)comprises:inserting a first layer of a completed card corresponding insize to the main surface of the card body to be produced in the recessof the die, thereafter, charging the recess with said measured quantityof molding compound, and then, optionally placing a second layer of thecompleted card corresponding in size to the main surface of the cardbody to be produced in said recess on the molding compound.
 8. Themethod for producing a data carrier of claim 7, wherein at least one ofthe first and second layers inserted in the recess contains anadditional data-carrying element.
 9. The method for producing a datacarrier of claim 1, wherein the recess in the die has raised areas forforming, when the molding compound is pressed, recesses in the card bodyinto which said element can later be embedded.
 10. The method forproducing a data carrier of claim 2 wherein the element is an electronicmodule for noncontacting data exchange.
 11. The method for producing adata carrier of claim 3, wherein the element is an electronic module.12. The method for producing a data carrier of claim 3, wherein theelement is a magnetic stripe.